I am having a similar issue. Last week I tested DOD and it worked, now it acts like it's not seeing the internet. Running the network tool shows that the DVR acknowledges that it can see my network just fine, but it claims that it can't connect to the internet (sometimes it returns error 22, sometimes error 62, but both seem to say the same thing). I can see in my router that it is renewing IP leases. I can ping the DVR from another PC on the network. Other PCs have no problem getting to the internet. I have no restrictions in the router that should affect this, and nothing has been changed in the router since last week when DOD worked. I've had no power outages... everything is on a UPS. I've tried doing a reset on the network settings, then re-running setup. I've restarted the DVR. I've rebooted the router. The only things that have changed are: I added an external drive, I've added the AM21, and it got a software update.
How does it test for internet connectivity? I assume it trys to ping a DirecTV server? If so, I could try to do the same on my PC to see if it is the DVR, or something between me and DirecTV.